How to set minimum upload size in codeigniter

I want to set minimum width and height for uploading images in codeigniter. The code is shown below.

$config['max_width']  = '480';
$config['max_height']  = '270';
$this->upload->do_upload()

I have set maximum cut off for this but how to set minimum ??

标签： codeigniter codeigniter-2

2条回答

Juvenile、少年°

2楼-- · 2019-08-23 06:50

Copy your Upload.php from system/libraries and paste on application/libraries. Then, introduce 2 new variables.

public $max_width               = 0;
public $max_height              = 0;
public $min_width               = 0; // new
public $min_height              = 0; // new

Add these to the initialize function so that you can pass values through a $config variable.

Locate is_allowed_dimensions function and modify it.

if ($this->min_width > 0 AND $D['0'] < $this->min_width)
{
    return FALSE;
}
if ($this->min_height > 0 AND $D['1'] < $this->min_height)
{
    return FALSE;
}

Check the upload language file and alter the upload_invalid_dimensions key accordingly to fit your case.

Have not tested this, but should work :)

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劫难

3楼-- · 2019-08-23 06:52

Here is the working fix, additionally you need to specify min_height and min_width while you init

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');


class CI_Upload {

public $max_size                = 0;
public $max_width              = 0;
public $max_height            = 0;
public $min_width              = 0;
public $min_height            = 0;
public $max_filename            = 0;
public $allowed_types          = "";
public $file_temp              = "";
public $file_name              = "";
public $orig_name              = "";
public $file_type              = "";
public $file_size              = "";
public $file_ext                = "";
public $upload_path          = "";
public $overwrite              = FALSE;
public $encrypt_name            = FALSE;
public $is_image                = FALSE;
public $image_width          = '';
public $image_height            = '';
public $image_type              = '';
public $image_size_str          = '';
public $error_msg               = array();
public $mimes                   = array();
public $remove_spaces           = TRUE;
public $xss_clean               = FALSE;
public $temp_prefix             = "temp_file_";
public $client_name             = '';

protected $_file_name_override  = '';

/**
 * Constructor
 *
 * @access  public
 */
public function __construct($props = array())
{
    if (count($props) > 0)
    {
        $this->initialize($props);
    }

    log_message('debug', "Upload Class Initialized");
}

// --------------------------------------------------------------------

/**
 * Initialize preferences
 *
 * @param   array
 * @return  void
 */
public function initialize($config = array())
{
    $defaults = array(
                        'max_size'          => 0,
                        'max_width'        => 0,
                        'max_height'          => 0,
                        'min_width'        => 0,
                        'min_height'          => 0,
                        'max_filename'      => 0,
                        'allowed_types'     => "",
                        'file_temp'         => "",
                        'file_name'         => "",
                        'orig_name'         => "",
                        'file_type'         => "",
                        'file_size'         => "",
                        'file_ext'          => "",
                        'upload_path'       => "",
                        'overwrite'         => FALSE,
                        'encrypt_name'      => FALSE,
                        'is_image'          => FALSE,
                        'image_width'       => '',
                        'image_height'      => '',
                        'image_type'        => '',
                        'image_size_str'    => '',
                        'error_msg'         => array(),
                        'mimes'             => array(),
                        'remove_spaces'     => TRUE,
                        'xss_clean'         => FALSE,
                        'temp_prefix'       => "temp_file_",
                        'client_name'       => ''
                    );


    foreach ($defaults as $key => $val)
    {
        if (isset($config[$key]))
        {
            $method = 'set_'.$key;
            if (method_exists($this, $method))
            {
                $this->$method($config[$key]);
            }
            else
            {
                $this->$key = $config[$key];
            }
        }
        else
        {
            $this->$key = $val;
        }
    }

    // if a file_name was provided in the config, use it instead of the user input
    // supplied file name for all uploads until initialized again
    $this->_file_name_override = $this->file_name;
}

// --------------------------------------------------------------------

/**
 * Perform the file upload
 *
 * @return  bool
 */
public function do_upload($field = 'userfile')
{

// Is $_FILES[$field] set? If not, no reason to continue.
    if ( ! isset($_FILES[$field]))
    {
        $this->set_error('upload_no_file_selected');
        return FALSE;
    }

    // Is the upload path valid?
    if ( ! $this->validate_upload_path())
    {
        // errors will already be set by validate_upload_path() so just return FALSE
        return FALSE;
    }

    // Was the file able to be uploaded? If not, determine the reason why.
    if ( ! is_uploaded_file($_FILES[$field]['tmp_name']))
    {
        $error = ( ! isset($_FILES[$field]['error'])) ? 4 : $_FILES[$field]['error'];

        switch($error)
        {
            case 1: // UPLOAD_ERR_INI_SIZE
                $this->set_error('upload_file_exceeds_limit');
                break;
            case 2: // UPLOAD_ERR_FORM_SIZE
                $this->set_error('upload_file_exceeds_form_limit');
                break;
            case 3: // UPLOAD_ERR_PARTIAL
                $this->set_error('upload_file_partial');
                break;
            case 4: // UPLOAD_ERR_NO_FILE
                $this->set_error('upload_no_file_selected');
                break;
            case 6: // UPLOAD_ERR_NO_TMP_DIR
                $this->set_error('upload_no_temp_directory');
                break;
            case 7: // UPLOAD_ERR_CANT_WRITE
                $this->set_error('upload_unable_to_write_file');
                break;
            case 8: // UPLOAD_ERR_EXTENSION
                $this->set_error('upload_stopped_by_extension');
                break;
            default :   $this->set_error('upload_no_file_selected');
                break;
        }

        return FALSE;
    }


    // Set the uploaded data as class variables
    $this->file_temp = $_FILES[$field]['tmp_name'];
    $this->file_size = $_FILES[$field]['size'];
    $this->_file_mime_type($_FILES[$field]);
    $this->file_type = preg_replace("/^(.+?);.*$/", "\\1", $this->file_type);
    $this->file_type = strtolower(trim(stripslashes($this->file_type), '"'));
    $this->file_name = $this->_prep_filename($_FILES[$field]['name']);
    $this->file_ext  = $this->get_extension($this->file_name);
    $this->client_name = $this->file_name;

    // Is the file type allowed to be uploaded?
    if ( ! $this->is_allowed_filetype())
    {
        $this->set_error('upload_invalid_filetype');
        return FALSE;
    }

    // if we're overriding, let's now make sure the new name and type is allowed
    if ($this->_file_name_override != '')
    {
        $this->file_name = $this->_prep_filename($this->_file_name_override);

        // If no extension was provided in the file_name config item, use the uploaded one
        if (strpos($this->_file_name_override, '.') === FALSE)
        {
            $this->file_name .= $this->file_ext;
        }

        // An extension was provided, lets have it!
        else
        {
            $this->file_ext  = $this->get_extension($this->_file_name_override);
        }

        if ( ! $this->is_allowed_filetype(TRUE))
        {
            $this->set_error('upload_invalid_filetype');
            return FALSE;
        }
    }

    // Convert the file size to kilobytes
    if ($this->file_size > 0)
    {
        $this->file_size = round($this->file_size/1024, 2);
    }

    // Is the file size within the allowed maximum?
    if ( ! $this->is_allowed_filesize())
    {
        $this->set_error('upload_invalid_filesize');
        return FALSE;
    }

    // Are the image dimensions within the allowed size?
    // Note: This can fail if the server has an open_basdir restriction.
    if ( ! $this->is_allowed_dimensions())
    {
        $this->set_error('upload_invalid_dimensions');
        return FALSE;
    }

    // Sanitize the file name for security
    $this->file_name = $this->clean_file_name($this->file_name);

    // Truncate the file name if it's too long
    if ($this->max_filename > 0)
    {
        $this->file_name = $this->limit_filename_length($this->file_name, $this->max_filename);
    }

    // Remove white spaces in the name
    if ($this->remove_spaces == TRUE)
    {
        $this->file_name = preg_replace("/\s+/", "_", $this->file_name);
    }

    /*
     * Validate the file name
     * This function appends an number onto the end of
     * the file if one with the same name already exists.
     * If it returns false there was a problem.
     */
    $this->orig_name = $this->file_name;

    if ($this->overwrite == FALSE)
    {
        $this->file_name = $this->set_filename($this->upload_path, $this->file_name);

        if ($this->file_name === FALSE)
        {
            return FALSE;
        }
    }

    /*
     * Run the file through the XSS hacking filter
     * This helps prevent malicious code from being
     * embedded within a file.  Scripts can easily
     * be disguised as images or other file types.
     */
    if ($this->xss_clean)
    {
        if ($this->do_xss_clean() === FALSE)
        {
            $this->set_error('upload_unable_to_write_file');
            return FALSE;
        }
    }

    /*
     * Move the file to the final destination
     * To deal with different server configurations
     * we'll attempt to use copy() first.  If that fails
     * we'll use move_uploaded_file().  One of the two should
     * reliably work in most environments
     */
    if ( ! @copy($this->file_temp, $this->upload_path.$this->file_name))
    {
        if ( ! @move_uploaded_file($this->file_temp, $this->upload_path.$this->file_name))
        {
            $this->set_error('upload_destination_error');
            return FALSE;
        }
    }

    /*
     * Set the finalized image dimensions
     * This sets the image width/height (assuming the
     * file was an image).  We use this information
     * in the "data" function.
     */
    $this->set_image_properties($this->upload_path.$this->file_name);

    return TRUE;
}

// --------------------------------------------------------------------

/**
 * Finalized Data Array
 *
 * Returns an associative array containing all of the information
 * related to the upload, allowing the developer easy access in one array.
 *
 * @return  array
 */
public function data()
{
    return array (
                    'file_name'         => $this->file_name,
                    'file_type'         => $this->file_type,
                    'file_path'         => $this->upload_path,
                    'full_path'         => $this->upload_path.$this->file_name,
                    'raw_name'          => str_replace($this->file_ext, '', $this->file_name),
                    'orig_name'         => $this->orig_name,
                    'client_name'       => $this->client_name,
                    'file_ext'          => $this->file_ext,
                    'file_size'         => $this->file_size,
                    'is_image'          => $this->is_image(),
                    'image_width'       => $this->image_width,
                    'image_height'      => $this->image_height,
                    'image_type'        => $this->image_type,
                    'image_size_str'    => $this->image_size_str,
                );
}

// --------------------------------------------------------------------

/**
 * Set Upload Path
 *
 * @param   string
 * @return  void
 */
public function set_upload_path($path)
{
    // Make sure it has a trailing slash
    $this->upload_path = rtrim($path, '/').'/';
}

// --------------------------------------------------------------------

/**
 * Set the file name
 *
 * This function takes a filename/path as input and looks for the
 * existence of a file with the same name. If found, it will append a
 * number to the end of the filename to avoid overwriting a pre-existing file.
 *
 * @param   string
 * @param   string
 * @return  string
 */
public function set_filename($path, $filename)
{
    if ($this->encrypt_name == TRUE)
    {
        mt_srand();
        $filename = md5(uniqid(mt_rand())).$this->file_ext;
    }

    if ( ! file_exists($path.$filename))
    {
        return $filename;
    }

    $filename = str_replace($this->file_ext, '', $filename);

    $new_filename = '';
    for ($i = 1; $i < 100; $i++)
    {
        if ( ! file_exists($path.$filename.$i.$this->file_ext))
        {
            $new_filename = $filename.$i.$this->file_ext;
            break;
        }
    }

    if ($new_filename == '')
    {
        $this->set_error('upload_bad_filename');
        return FALSE;
    }
    else
    {
        return $new_filename;
    }
}

// --------------------------------------------------------------------

/**
 * Set Maximum File Size
 *
 * @param   integer
 * @return  void
 */
public function set_max_filesize($n)
{
    $this->max_size = ((int) $n < 0) ? 0: (int) $n;
}

// --------------------------------------------------------------------

/**
 * Set Maximum File Name Length
 *
 * @param   integer
 * @return  void
 */
public function set_max_filename($n)
{
    $this->max_filename = ((int) $n < 0) ? 0: (int) $n;
}

// --------------------------------------------------------------------

/**
 * Set Maximum Image Width
 *
 * @param   integer
 * @return  void
 */
public function set_max_width($n)
{
    $this->max_width = ((int) $n < 0) ? 0: (int) $n;
}

public function set_min_width($n)
{
    $this->min_width = ((int) $n < 0) ? 0: (int) $n;
}

// --------------------------------------------------------------------

/**
 * Set Maximum Image Height
 *
 * @param   integer
 * @return  void
 */
public function set_max_height($n)
{
    $this->max_height = ((int) $n < 0) ? 0: (int) $n;
}

public function set_min_height($n)
{
    $this->min_height = ((int) $n < 0) ? 0: (int) $n;
}

// --------------------------------------------------------------------

/**
 * Set Allowed File Types
 *
 * @param   string
 * @return  void
 */
public function set_allowed_types($types)
{
    if ( ! is_array($types) && $types == '*')
    {
        $this->allowed_types = '*';
        return;
    }
    $this->allowed_types = explode('|', $types);
}

// --------------------------------------------------------------------

/**
 * Set Image Properties
 *
 * Uses GD to determine the width/height/type of image
 *
 * @param   string
 * @return  void
 */
public function set_image_properties($path = '')
{
    if ( ! $this->is_image())
    {
        return;
    }

    if (function_exists('getimagesize'))
    {
        if (FALSE !== ($D = @getimagesize($path)))
        {
            $types = array(1 => 'gif', 2 => 'jpeg', 3 => 'png');

            $this->image_width      = $D['0'];
            $this->image_height     = $D['1'];
            $this->image_type       = ( ! isset($types[$D['2']])) ? 'unknown' : $types[$D['2']];
            $this->image_size_str   = $D['3'];  // string containing height and width
        }
    }
}

// --------------------------------------------------------------------

/**
 * Set XSS Clean
 *
 * Enables the XSS flag so that the file that was uploaded
 * will be run through the XSS filter.
 *
 * @param   bool
 * @return  void
 */
public function set_xss_clean($flag = FALSE)
{
    $this->xss_clean = ($flag == TRUE) ? TRUE : FALSE;
}

// --------------------------------------------------------------------

/**
 * Validate the image
 *
 * @return  bool
 */
public function is_image()
{
    // IE will sometimes return odd mime-types during upload, so here we just standardize all
    // jpegs or pngs to the same file type.

    $png_mimes  = array('image/x-png');
    $jpeg_mimes = array('image/jpg', 'image/jpe', 'image/jpeg', 'image/pjpeg');

    if (in_array($this->file_type, $png_mimes))
    {
        $this->file_type = 'image/png';
    }

    if (in_array($this->file_type, $jpeg_mimes))
    {
        $this->file_type = 'image/jpeg';
    }

    $img_mimes = array(
                        'image/gif',
                        'image/jpeg',
                        'image/png',
                    );

    return (in_array($this->file_type, $img_mimes, TRUE)) ? TRUE : FALSE;
}

// --------------------------------------------------------------------

/**
 * Verify that the filetype is allowed
 *
 * @return  bool
 */
public function is_allowed_filetype($ignore_mime = FALSE)
{
    if ($this->allowed_types == '*')
    {
        return TRUE;
    }

    if (count($this->allowed_types) == 0 OR ! is_array($this->allowed_types))
    {
        $this->set_error('upload_no_file_types');
        return FALSE;
    }

    $ext = strtolower(ltrim($this->file_ext, '.'));

    if ( ! in_array($ext, $this->allowed_types))
    {
        return FALSE;
    }

    // Images get some additional checks
    $image_types = array('gif', 'jpg', 'jpeg', 'png', 'jpe');

    if (in_array($ext, $image_types))
    {
        if (getimagesize($this->file_temp) === FALSE)
        {
            return FALSE;
        }
    }

    if ($ignore_mime === TRUE)
    {
        return TRUE;
    }

    $mime = $this->mimes_types($ext);

    if (is_array($mime))
    {
        if (in_array($this->file_type, $mime, TRUE))
        {
            return TRUE;
        }
    }
    elseif ($mime == $this->file_type)
    {
            return TRUE;
    }

    return FALSE;
}

// --------------------------------------------------------------------

/**
 * Verify that the file is within the allowed size
 *
 * @return  bool
 */
public function is_allowed_filesize()
{
    if ($this->max_size != 0  AND  $this->file_size > $this->max_size)
    {
        return FALSE;
    }
    else
    {
        return TRUE;
    }
}

// --------------------------------------------------------------------

/**
 * Verify that the image is within the allowed width/height
 *
 * @return  bool
 */
public function is_allowed_dimensions()
{
    if ( ! $this->is_image())
    {
        return TRUE;
    }

    if (function_exists('getimagesize'))
    {
        $D = @getimagesize($this->file_temp);

        if ($this->max_width > 0 AND $D['0'] > $this->max_width)
        {
            return FALSE;
        }

        if ($this->max_height > 0 AND $D['1'] > $this->max_height)
        {
            return FALSE;
        }

        if ($D['0'] < $this->min_width)
        {
            return FALSE;
        }

        if ($D['1'] < $this->min_height)
        {
            return FALSE;
        }

        return TRUE;
    }

    return TRUE;
}

// --------------------------------------------------------------------

/**
 * Validate Upload Path
 *
 * Verifies that it is a valid upload path with proper permissions.
 *
 *
 * @return  bool
 */
public function validate_upload_path()
{
    if ($this->upload_path == '')
    {
        $this->set_error('upload_no_filepath');
        return FALSE;
    }

    if (function_exists('realpath') AND @realpath($this->upload_path) !== FALSE)
    {
        $this->upload_path = str_replace("\\", "/", realpath($this->upload_path));
    }

    if ( ! @is_dir($this->upload_path))
    {
        $this->set_error('upload_no_filepath');
        return FALSE;
    }

    if ( ! is_really_writable($this->upload_path))
    {
        $this->set_error('upload_not_writable');
        return FALSE;
    }

    $this->upload_path = preg_replace("/(.+?)\/*$/", "\\1/",  $this->upload_path);
    return TRUE;
}

// --------------------------------------------------------------------

/**
 * Extract the file extension
 *
 * @param   string
 * @return  string
 */
public function get_extension($filename)
{
    $x = explode('.', $filename);
    return '.'.end($x);
}

// --------------------------------------------------------------------

/**
 * Clean the file name for security
 *
 * @param   string
 * @return  string
 */
public function clean_file_name($filename)
{
    $bad = array(
                    "<!--",
                    "-->",
                    "'",
                    "<",
                    ">",
                    '"',
                    '&',
                    '$',
                    '=',
                    ';',
                    '?',
                    '/',
                    "%20",
                    "%22",
                    "%3c",      // <
                    "%253c",    // <
                    "%3e",      // >
                    "%0e",      // >
                    "%28",      // (
                    "%29",      // )
                    "%2528",    // (
                    "%26",      // &
                    "%24",      // $
                    "%3f",      // ?
                    "%3b",      // ;
                    "%3d"       // =
                );

    $filename = str_replace($bad, '', $filename);

    return stripslashes($filename);
}

// --------------------------------------------------------------------

/**
 * Limit the File Name Length
 *
 * @param   string
 * @return  string
 */
public function limit_filename_length($filename, $length)
{
    if (strlen($filename) < $length)
    {
        return $filename;
    }

    $ext = '';
    if (strpos($filename, '.') !== FALSE)
    {
        $parts      = explode('.', $filename);
        $ext        = '.'.array_pop($parts);
        $filename   = implode('.', $parts);
    }

    return substr($filename, 0, ($length - strlen($ext))).$ext;
}

// --------------------------------------------------------------------

/**
 * Runs the file through the XSS clean function
 *
 * This prevents people from embedding malicious code in their files.
 * I'm not sure that it won't negatively affect certain files in unexpected ways,
 * but so far I haven't found that it causes trouble.
 *
 * @return  void
 */
public function do_xss_clean()
{
    $file = $this->file_temp;

    if (filesize($file) == 0)
    {
        return FALSE;
    }

    if (function_exists('memory_get_usage') && memory_get_usage() && ini_get('memory_limit') != '')
    {
        $current = ini_get('memory_limit') * 1024 * 1024;

        // There was a bug/behavioural change in PHP 5.2, where numbers over one million get output
        // into scientific notation.  number_format() ensures this number is an integer
        // http://bugs.php.net/bug.php?id=43053

        $new_memory = number_format(ceil(filesize($file) + $current), 0, '.', '');

        ini_set('memory_limit', $new_memory); // When an integer is used, the value is measured in bytes. - PHP.net
    }

    // If the file being uploaded is an image, then we should have no problem with XSS attacks (in theory), but
    // IE can be fooled into mime-type detecting a malformed image as an html file, thus executing an XSS attack on anyone
    // using IE who looks at the image.  It does this by inspecting the first 255 bytes of an image.  To get around this
    // CI will itself look at the first 255 bytes of an image to determine its relative safety.  This can save a lot of
    // processor power and time if it is actually a clean image, as it will be in nearly all instances _except_ an
    // attempted XSS attack.

    if (function_exists('getimagesize') && @getimagesize($file) !== FALSE)
    {
        if (($file = @fopen($file, 'rb')) === FALSE) // "b" to force binary
        {
            return FALSE; // Couldn't open the file, return FALSE
        }

        $opening_bytes = fread($file, 256);
        fclose($file);

        // These are known to throw IE into mime-type detection chaos
        // <a, <body, <head, <html, <img, <plaintext, <pre, <script, <table, <title
        // title is basically just in SVG, but we filter it anyhow

        if ( ! preg_match('/<(a|body|head|html|img|plaintext|pre|script|table|title)[\s>]/i', $opening_bytes))
        {
            return TRUE; // its an image, no "triggers" detected in the first 256 bytes, we're good
        }
        else
        {
            return FALSE;
        }
    }

    if (($data = @file_get_contents($file)) === FALSE)
    {
        return FALSE;
    }

    $CI =& get_instance();
    return $CI->security->xss_clean($data, TRUE);
}

// --------------------------------------------------------------------

/**
 * Set an error message
 *
 * @param   string
 * @return  void
 */
public function set_error($msg)
{
    $CI =& get_instance();
    $CI->lang->load('upload');

    if (is_array($msg))
    {
        foreach ($msg as $val)
        {
            $msg = ($CI->lang->line($val) == FALSE) ? $val : $CI->lang->line($val);
            $this->error_msg[] = $msg;
            log_message('error', $msg);
        }
    }
    else
    {
        $msg = ($CI->lang->line($msg) == FALSE) ? $msg : $CI->lang->line($msg);
        $this->error_msg[] = $msg;
        log_message('error', $msg);
    }
}

// --------------------------------------------------------------------

/**
 * Display the error message
 *
 * @param   string
 * @param   string
 * @return  string
 */
public function display_errors($open = '<p>', $close = '</p>')
{
    $str = '';
    foreach ($this->error_msg as $val)
    {
        $str .= $open.$val.$close;
    }

    return $str;
}

// --------------------------------------------------------------------

/**
 * List of Mime Types
 *
 * This is a list of mime types.  We use it to validate
 * the "allowed types" set by the developer
 *
 * @param   string
 * @return  string
 */
public function mimes_types($mime)
{
    global $mimes;

    if (count($this->mimes) == 0)
    {
        if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
        {
            include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
        }
        elseif (is_file(APPPATH.'config/mimes.php'))
        {
            include(APPPATH.'config//mimes.php');
        }
        else
        {
            return FALSE;
        }

        $this->mimes = $mimes;
        unset($mimes);
    }

    return ( ! isset($this->mimes[$mime])) ? FALSE : $this->mimes[$mime];
}

// --------------------------------------------------------------------

/**
 * Prep Filename
 *
 * Prevents possible script execution from Apache's handling of files multiple extensions
 * http://httpd.apache.org/docs/1.3/mod/mod_mime.html#multipleext
 *
 * @param   string
 * @return  string
 */
protected function _prep_filename($filename)
{
    if (strpos($filename, '.') === FALSE OR $this->allowed_types == '*')
    {
        return $filename;
    }

    $parts      = explode('.', $filename);
    $ext        = array_pop($parts);
    $filename   = array_shift($parts);

    foreach ($parts as $part)
    {
        if ( ! in_array(strtolower($part), $this->allowed_types) OR $this->mimes_types(strtolower($part)) === FALSE)
        {
            $filename .= '.'.$part.'_';
        }
        else
        {
            $filename .= '.'.$part;
        }
    }

    $filename .= '.'.$ext;

    return $filename;
}

// --------------------------------------------------------------------

/**
 * File MIME type
 *
 * Detects the (actual) MIME type of the uploaded file, if possible.
 * The input array is expected to be $_FILES[$field]
 *
 * @param   array
 * @return  void
 */
protected function _file_mime_type($file)
{
    // We'll need this to validate the MIME info string (e.g. text/plain; charset=us-ascii)
    $regexp = '/^([a-z\-]+\/[a-z0-9\-\.\+]+)(;\s.+)?$/';

    /* Fileinfo extension - most reliable method
     *
     * Unfortunately, prior to PHP 5.3 - it's only available as a PECL extension and the
     * more convenient FILEINFO_MIME_TYPE flag doesn't exist.
     */
    if (function_exists('finfo_file'))
    {
        $finfo = finfo_open(FILEINFO_MIME);
        if (is_resource($finfo)) // It is possible that a FALSE value is returned, if there is no magic MIME database file found on the system
        {
            $mime = @finfo_file($finfo, $file['tmp_name']);
            finfo_close($finfo);

            /* According to the comments section of the PHP manual page,
             * it is possible that this function returns an empty string
             * for some files (e.g. if they don't exist in the magic MIME database)
             */
            if (is_string($mime) && preg_match($regexp, $mime, $matches))
            {
                $this->file_type = $matches[1];
                return;
            }
        }
    }

    /* This is an ugly hack, but UNIX-type systems provide a "native" way to detect the file type,
     * which is still more secure than depending on the value of $_FILES[$field]['type'], and as it
     * was reported in issue #750 (https://github.com/EllisLab/CodeIgniter/issues/750) - it's better
     * than mime_content_type() as well, hence the attempts to try calling the command line with
     * three different functions.
     *
     * Notes:
     *  - the DIRECTORY_SEPARATOR comparison ensures that we're not on a Windows system
     *  - many system admins would disable the exec(), shell_exec(), popen() and similar functions
     *    due to security concerns, hence the function_exists() checks
     */
    if (DIRECTORY_SEPARATOR !== '\\')
    {
        $cmd = 'file --brief --mime ' . escapeshellarg($file['tmp_name']) . ' 2>&1';

        if (function_exists('exec'))
        {
            /* This might look confusing, as $mime is being populated with all of the output when set in the second parameter.
             * However, we only neeed the last line, which is the actual return value of exec(), and as such - it overwrites
             * anything that could already be set for $mime previously. This effectively makes the second parameter a dummy
             * value, which is only put to allow us to get the return status code.
             */
            $mime = @exec($cmd, $mime, $return_status);
            if ($return_status === 0 && is_string($mime) && preg_match($regexp, $mime, $matches))
            {
                $this->file_type = $matches[1];
                return;
            }
        }

        if ( (bool) @ini_get('safe_mode') === FALSE && function_exists('shell_exec'))
        {
            $mime = @shell_exec($cmd);
            if (strlen($mime) > 0)
            {
                $mime = explode("\n", trim($mime));
                if (preg_match($regexp, $mime[(count($mime) - 1)], $matches))
                {
                    $this->file_type = $matches[1];
                    return;
                }
            }
        }

        if (function_exists('popen'))
        {
            $proc = @popen($cmd, 'r');
            if (is_resource($proc))
            {
                $mime = @fread($proc, 512);
                @pclose($proc);
                if ($mime !== FALSE)
                {
                    $mime = explode("\n", trim($mime));
                    if (preg_match($regexp, $mime[(count($mime) - 1)], $matches))
                    {
                        $this->file_type = $matches[1];
                        return;
                    }
                }
            }
        }
    }

    // Fall back to the deprecated mime_content_type(), if available (still better than $_FILES[$field]['type'])
    if (function_exists('mime_content_type'))
    {
        $this->file_type = @mime_content_type($file['tmp_name']);
        if (strlen($this->file_type) > 0) // It's possible that mime_content_type() returns FALSE or an empty string
        {
            return;
        }
    }

    $this->file_type = $file['type'];
}

// --------------------------------------------------------------------

}

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